Search results for "Rill"

“AD HOC” MODIFIED CLAYS FOR BIOTECHNOLOGICAL APPLICATIONS

Nowadays, the scientific community has to face with cogent problems strictly linked to the improvement of quality of live. Among the different tasks to achieve the prefixed objective the focus has been put on the drug administration, i.e., attention has been paid to propose an appropriate solution to improve the performance of a drug delivery system and to eliminate both the side effect and drawbacks. With the aim to achieve the design, synthesis, and characterization of versatile systems, with peculiar characteristics, based on clays and clays modified with a biocompatible surfactant, able to adsorb and release organic substances of pharmaceutical interest the present PhD thesis has been u…

Effect of the indentation process on fatigue life of drilled specimens

2015

Design and manufacture of mechanical elements are strongly influenced by the evaluation of the residual stresses due to their effects on the material strength. This paper presents numerical and experimental results performed on AW 6082-T6 aluminum alloy drilled specimens when the hole is created after a bilateral indentation process. The plastic deformation induced by the indenters creates a compressive residual stress field around the hole, which persists after the drilling operation. Several numerical analysis have been carried out in ANSYS APDL explicit solver for different indentation depths and hole diameters in order to evaluate the compressive circumferential stresses, optimal proces…

Introduction and Technical Survey: Protein Aggregation and Fibrillogenesis

2012

In this chapter we provided the overall background to the subject of protein aggregation and fibrillogenesis in amyloidogenesis, with introduction and brief discussion of the various topics that are included with the coming chapters. The division of the book into basic science and clinical science sections enables correlation of the topics to be made. The many proteins and peptides that have currently been found to undergo fibrillogenesis are tabulated. A broad technical survey is made, to indicate the vast array of techniques currently available to study aspects of protein oligomerization, aggregation and fibrillogenesis. These are split into three groups and tabulated, as the microscopica…

Krill herd algorithm-based neural network in structural seismic reliability evaluation

2018

ABSTRACTIn this research work, the relative displacement of the stories has been determined by means of a feedforward Artificial Neural Network (ANN) model, which employs one of the novel methods for the optimization of the artificial neural network weights, namely the krill herd algorithm. For the purpose of this work, the area, elasticity, and load parameters were the input parameters and the relative displacement of the stories was the output parameter. To assess the precision of the feedforward (FF) model optimized using the Krill Herd Optimization (FF-KH) algorithm, comparison of results has been performed relative to the results obtained by the linear regression model, the Genetic Alg…

Atrial activity extraction for atrial fibrillation analysis using blind source separation.

2004

This contribution addresses the extraction of atrial activity (AA) from real electrocardiogram (ECG) recordings of atrial fibrillation (AF). We show the appropriateness of independent component analysis (ICA) to tackle this biomedical challenge when regarded as a blind source separation (BSS) problem. ICA is a statistical tool able to reconstruct the unobservable independent sources of bioelectric activity which generate, through instantaneous linear mixing, a measurable set of signals. The three key hypothesis that make ICA applicable in the present scenario are discussed and validated: 1) AA and ventricular activity (VA) are generated by sources of independent bioelectric activity; 2) AA …

Feature Selection Methods to Extract Knowledge and Enhance Analysis of Ventricular Fibrillation Signals

2014

Study of drilling and welding laser : dynamics of keyhole

2011

The aim of the present work is to study experimentally the formation of the capillary during the drilling and welding by laser beam and to develop the numerical simulation which allows following the dynamics and the evolution of the keyhole. The zinc was chosen as a test material because its thermodynamical properties are well known. To simplify the problem, in the first place the drilling mechanism was studied. Two experimental methods were used to characterize the evolution of the keyhole: the Direct Observation of Drilled Hole method, which allows the visualization of the keyhole after the application of laser pulses of different durations, and Zn-Quartz method, which allows the direct o…

Replica field theory for anharmonic sound attenuation in glasses

2011

Abstract A saddle-point treatment of interacting phonons in a disordered environment is developed. In contrast to crystalline solids, anharmonic attenuation of density fluctuations becomes important in the hydrodynamic regime, due to a broken momentum conservation. The variance of the shear modulus Δ2 turns out to be the strength of the disorder enhanced phonon–phonon interaction. In the low-frequency regime (below the boson peak frequency) we obtain an Akhiezer-like sound attenuation law Γ ∝ Τω2. Together with the usual Rayleigh scattering mechanism this yields a crossover of the Brillouin linewidth from a ω2 to a ω4 regime. The crossover frequency ωc is fully determined by the boson peak …

Anomalous thermoelastic behavior of (KI)1-x(NH4I)x

1990

Abstract An anomalous softening of the shear mode c 44 is observed in (KI) 1- x (NH 4 I) x with Brillouin scattering (10 K ⩽ T ⩽ 300 K ). It is caused by the weak quadrupolar moment of the NH 4 + ion, induced by the C 3 v symmetry of the potential. A parallel decrease of the lifetime of this transverse phonon at lower temperatures is observed. Static random strain fields due to admixing KI with NH 4 I are small. The results have been treated in terms of a mean field theory. The c 11 elastic constant does not show any anomalous behavior. Also are given the elastic constants c 11 and c 44 for x =0.14, 0.43 and 1 and 1 at T = 300 K and 10 K .

La influencia de dialectos chinos en el aprendizaje de la pronunciación de español :

2019

Resumen: Este trabajo pretende mostrar la influencia fonológica de los dialectos chinos en el aprendizaje de español tomando el shanghainés como ejemplo. Se hace una comparación entre el inventario consonántico y vocálico, así como la entonación del dialecto shanghainés y del chino mandarín para encontrar las características fonológicas propias del primero que ayudan en el aprendizaje del español. La investigación revela que se facilita la pronunciación de las consonantes oclusivas sonoras y la entonación menos marcada para los hablantes del shanghainés gracias a su dialecto pero no les resultan fáciles los grupos consonánticos ni la vibrante. El gran número de consonantes nasales en el chi…